839 FO09 – The proportion of tackles and ball-carries resulting in head acceleration events (HAE) >20g in men’s rugby league players is <13%: Time to focus prevention strategies

Background Rugby league is a contact sport, with a high rate of concussion, although limited research has evaluated the incidence of head acceleration events (HAEs) using instrumented mouthguards (iMGs). Previous research indicates that most HAEs are caused by tackles and ball-carries, although the proportion of these events resulting in HAEs is unknown. Objective Describe and compare the incidence of HAEs and the proportion of tackles and carries resulting in HAEs in elite level men's rugby league using iMGs and video analysis. Design Prospective cohort. Setting Professional rugby players from one men's competition (Super League). Participants Sixty-four professional male rugby league players across 731 player-matches. Main Outcome Measurements Incidence rates were calculated as the number of HAEs (as recorded by iMGs) per player-hour. Proportions were calculated as the percentage of tackles and ball-carries resulting in an HAE. Values are reported across a range of peak linear acceleration thresholds with 95% confidence intervals (CI) for the Poisson distribution. Results The incidence (CI) of HAEs per player-hour, for forwards vs backs was 3.92 (1.00–8.00) vs 1.96 (0.00–5.00) between 20–40g (p<0.001), 0.40 (0.00–2.00) vs 0.27 (0.00–2.00) between 40–60g (p=0.002), and 0.08 (0.00–1.00) vs 0.06 (0.00–1.00) >60g (p=0.184). The proportion (CI) for tackles vs ball-carries to result in an HAEs was 12.86% (6.00–20.00%) vs 10.18% (4.00–17.00%) for HAEs >20g (p<0.001), 1.65% (0.00–5.00%) vs 1.30% (0.00–4.00%) for HAEs >40g (p=0.043%) and 0.24% (0.00–1.00%) vs 0.29% (0.00–2.00%) for HAE >60g (p=0.49). Conclusions Forwards experienced a significantly higher rate of HAEs between 20–40g and 40–60g magnitudes. A small proportion of tackles and ball-carries result in a HAE >20g, focusing injury prevention interventions on high magnitude events.